Stannic oxide-antimony tetroxide catalyst composition



United States Patent O" 3,198,751 STANNIC (BXlDE-ANTTMONY TETRQXZDECATALYST C(PMTQSITHON James Robert Bcthell and David James Hadley, EpsomDowns, and Barrie Wood, Epsom, England, assignors to The DistillersCompany Limited, Edinburgh, Scotland, a British company No Drawing.Original application Feb. 3, 1960, Ser. No. 6,365, new Patent No.3,094,565, dated June 18, 1963. Divided and this appiication Oct. 9,1962, Ser. No. 225,475

Claims priority, application Great Britain, Feb. 17, 1959, 5,397/59;Mar. 12, 1959, 8,678/59; Apr. 2, 1959, 11,272/59; Apr. 18, 1959,13,283/59; June 5, 1959, 19,228/59; Get. 9, 1959, 34,225/59, 34,226/59 1Claim. (Cl. 252-461) The present invention relates to the production ofunsaturated aliphatic aldehydes, and in particular to the production ofacrolcin and methacrolein and is a divisional of our prior copendingapplication Serial No. 6,365, filed February 3, 1960, now US. Patent3,094,565.

According to the present invention, the process for the production ofacrolein or methacrolein comprises reacting at an elevated temperaturein the vapour phase propylene or isobutene with oxygen in the presenceof an oxidation catalyst comprising antimony oxide.

The antimony oxide catalyst may be derived from an antimony compoundwhich is partially or completely converted under the reaction conditionsto an oxide of antimony. The catalyst may comprise antimony oxide aloneor in combination with another polyvalent metal oxide such as an oxideof molybdenum, tungsten, tellurium, copper, titanium or cobalt. Suchcatalyst-s may be regarded either as mixtures of antimony oxides with,for instance, molybdenum oxides, or as oxygen-containing compounds ofantimony with the other metal, i.e. antimony molybdate. Under thereaction conditions the catalyst may contain either or both forms. Suchcatalysts may be prepared, for instance, by intimately mixing ant monyoxide or hydroxide with the other metal oxide or hydroxide.Alternatively the catalyst may be prepared by precipitation, forinstance by adding an aqueous solution of an antimony salt to an aqueoussolution or susension of molybdic acid or a molybdic acid salt, andrecovering the resulting precipitate.

The activity of the antimony oxide catalysts is frequently improved by aprior heat-treatment, for instance at a temperature between 500 andl=100 C.

An outstandingly good catalyst comprises (i) a mixture of the oxides ofantimony and tin, and/or (ii) a compound of antimony, tin and oxygen,i.e. tin antimonate; under the reaction conditions the catalyst may bepresent in either or both forms. The catalyst may be prepared in anysuitable manner, for instance, by intimately mixing the oxides ofantimony and tin. Alternatively, compounds of tin or antimony, such asthe hydroxides, which on heating are partially or completely convertedto the oxides, may be used. One preferred method of preparing theantimony oxide/tin oxide catalyst comprises making a mixed solution ofcationic antimony and tin salts, adding a volatile base such as ammoniato form a precipitate, and recovering and heating the precipitate at atemperature between 500 and 1100 C. Particularly useful catalysts can beprepared in this way from stannous chloride and antimony pentachlor-ideby mixing them together in aqueous media and adding ammonia until the pHis greater than 5.0.

When the tin compound in the mixture is present in its lower valencystate, i.e. as a stannous compound, it is particularly preferred tosubject the precipitated mixture to a preliminary heat-treatment in anatmosphere comprising oxygen and an inert gas such as nitrogen, carbon3,193,751 Patented Aug. 3, 1965 dioxide or steam, the proportion ofoxygen and the total flow of gas being controlled so that no part of thecatalyst during this preliminary heat-treatment exceeds a temperature of500 C. After this preliminary heat-treatment, the mixture is thensubjected to a final heat-treatment in air at a temperature in the range500 to 1100 C.

Another particularly preferred method of preparing the antimonyoxide/tin oxide catalyst comprises intimately mixing stannic oxide withantimony pentoxide and/ or antimony tetroxide and heat-treating theresulting mixture. The oxidesare preferably made by the action ofaqueous nitric acid on the separate metals, and after mixing, the oxidesare preferably subjected to a preliminary heat-treatment at about 700750C., and subsequently to a final heat-treatment at a more elevatedtemperature, for instance up to 1100 C. and preferably between 1000 C.and 1050 C. The preliminary heat treatment is necessary in order toavoid partial fusion and/or volatilisation of the. antimony oxides.

The atomic ratio of tin to antimony in the catalysts may vary withinmoderately wide limits, for instance between 0l.1.:l and 10: 1. It isparticularly preferred to use tin/ antimony catalysts containingsubstantially no molybdenurn or tungsten, or compounds of these metals.

The antimony oxide catalysts used in the process of the presentinvention may, if desired, be deposited on supports such as alumina orsilica.

The reaction of propylene or isobutene with oxygen over the oxidationcatalyst may be carried out in any suitable manner, for instance as afixed bed process, or as a fluidised bed process.

The proportion of olefine in the feed may vary within fairly widelimits, for example between 1 and 20% by volume. -It is preferred to usebetween about 2 and 10% by volume of the olefine. The preferred olefineis propylene.

The concentration of oxygen in the feed may also vary within fairly widelimits for example between 1 and 20% by volume. It is preferred to usebetween about 2 and 10% by volume of the olefine. The preferred olefineis propylene.

The concentration of oxygen in the feed may also vary within fairly widelimits for example between -1 and 20% by volume and preferably between 2and 15% by volume. The oxygen may be diluted with inert gases, and maybe, for example, supplied as air.

It is preferred to carry out the reaction in the presence, as diluent,of a gas which is substantially inert under the conditions of reaction,for example nitrogen, propane, butane, isobutane, carbon dioxide andsteam. It is preferred to use steam or nitrogen or mixtures thereof. Theconcentration of the steam may vary within wide limits, for instancebetween 20% and by volume of the feed.

The reaction is carried out at an elevated temperature, preferablybetween 300 and 500 C.

The contact time may be, for example, in the range 1-30 seconds.

The aldehyde may be recovered from the reaction prodnot by anyconventional method, for example by countercurrent extraction withwater, preferably at a pH at or below 7, followed by fractionaldistillation.

The process of the invention is further illustrated by the followingexamples, in which parts by weight and parts by volume bear the samerelation to each other as do grams to millilitres.

Example 1 A catalyst was prepared in the following manner:

50.8% by weight of potassium pyroantimonate (K H Sb O- .4H O) wasdissolved in 750 parts by weight of hot water, and 22.6 parts by weightof stannous chloride 3 (SnCl .2I-l O) was dissolved in 50 parts byweight of hot water and 315 parts by weight of glacial acetic acid. Thetwo solutions were then mixed together, and the resultant precipitatewas filtered off, washed, dried and formed into granules.

The catalyst was placed in a reactor maintained at 360 C., and a gasmixture comprising 11.7% by volume of propylene, 9.8% by volume ofoxygen, 38.4% by volume of nitrogen and 40.1% by volume of steam Waspassed over the catalyst with a contact time of 4 seconds.

11.9% of the propylene fed was converted to acrolein and 3% to carbondioxide. 84.8% of the propylene was recovered unchanged. The yield ofacrolein based on propylene consumed was 78.2%.

Example 2 An antimony tungstate catalyst was prepared in the followingmanner.

Antimony pentoxide (32.35 parts by weight) and tungstic acid (75 partsby weight) were ground together with a small amount of water to form asmooth paste. The resultant mixture was dried, heated in air of 600 C.for 16 hours and formed into pellets. The catalyst was finally heated inair at 650 C. for 5 hours.

The catalyst was placed in a reactor maintained at 460 C. A gas mixturecomprising by volume of propylene, 50% of air and of steam was passedover the catalyst. The contact time was 4 seconds. 14% of the propylenefed was converted to acrolein and 5% to carbon dioxide. The yield ofacrolein based on propylene consumed was 61%.

Example 3 An antimony pentoxide catalyst was placed in a reactormaintained at 370 C. A gas mixture comprising 10% by volume ofpropylene, by volume of air and 40% of steam was passed over thecatalyst. The contact time was 4 seconds. 16% of the propylene fed wasconverted into acrolein and 4% into carbon dioxide. The yield ofacrolein based on propylene consumed was 64%.

Example 4 134.7 parts by weight of stannous oxide and 323.5 parts byweight of antimony pentoxide giving an atomic ratio of tinzantimony of0.5:1 were ground together for 16 hours, mixed to a smooth paste withwater, dried, pelleted, and heated in air at 540 C., for 16 hours.

The catalyst was placed in a reactor maintained at 400 C. A gas mixturecomprising 10% by volume of propylene, 49.3% by volume of air and 40.6%by volume of steam was passed over the catalyst. The contact time was 4seconds.

24.9% of the propylene fed was converted to acrolein and 9.0% to carbondioxide. The yield of acrolein based on propylene consumed was 59.5%.

Example 5 150.7 parts by weight of stannic oxide and 80.9 parts byweight of antimony pentoxide were ground to less than 100 mesh 13.8.8.and mixed to give a nominal atomic ratio of tin:antimony of 2:1. Themixture was ground together with water to form a smooth paste, dried at100 C., pelleted, and heated in air at 725 C. for 16 hours.

The catalyst was placed in a reactor maintained at 482 C., and a gasmixture comprising 10.6% by volume of propylene, 49.6% by volume of airand 39.8% by volume of steam was passed over the catalyst. The contacttime was 4- seconds.

32% ot the propylene fed was converted to acrolein and 4.9% to carbondioxide. The yield of acrolein based on propylene consumed was 75%.

Example 6 111.9 parts by weight of antimony pentachloride were addeddropwise to 2,000 parts by weight of vigorously stirred water. When thisaddition was complete a solution of 45.1 parts by weight of stannouschloride (SnCl 2I-l O) in 100 parts by weight of 1% hydrochloric acidwas added. The mixture was heated to C. and dilute ammonia solutionadded until the pH was 6.5. After boiling, the precipitate was filteredoff, washed by resuspension with 3,000 parts by weight of hot water,refiltered, dried at 120 C. and heated in air at 380 C., for 4 hours.Heating was then continued at 540 C. for 16 hours. The resultantcatalyst, which had a tinzantimony atomic ratio of about 0.5 :1 was thengranulated.

The catalyst was placed in a reactor maintained at 360 C. and agesmixture comprising 9.9% by volume of propylene, 51.3% by volume of airand 38.9% by volume of steam was passed over the catalyst. The con tacttime was 4 seconds.

29.0% of the propylene fed was converted to acrolein and 8.1% to carbondioxide. The yield of acrolein based on propylene consumed was 71.0%.

Example 7 A catalyst was prepared as described in Example 6 to give atinzantimony atomic ratio of about 3:1.

The catalyst was placed in a reactor maintained at 380 C. and a gasmixture comprising 10.1% by volume of propylene, 50.0% by volume of airand 39.9% by volume of steam was passed over the catalyst, the Contacttime being 4 seconds.

39.3% of the propylene fed was converted to acrolein and 6.9% to carbondioxide. The yield of acrolein based on propylene consumed was 72.6%.

Example 8 300.8 parts by weight of stannous chloride (SHC12.2H20) weredissolved in 300 parts by weight of 1% hydrochloric acid. This solutionwas added slowly to 3000 parts by weight of vigorously stirred water.Simultaneously, 132.9 parts by weight of antimony pentachloride wereadded dropwise, giving a tinzantimony atomic ratio of 3:1. When theaddition was complete the pH of the mixture was adjusted to between 5and 5.5 by the addition of dilute ammonia solution. After the additionof 500 parts by weight of water, the mixture Was cooled to 24 C. Theprecipitate was filtered, washed by resuspension in 3000 parts by weightof water and refiltered. The precipitate was dried at C. for 19 hoursand granulated. The granules (8-16 mesh B.S.S.) were heated from 350 C.to 450 C. in a stream of nitrogen, before introducing a small flow ofair. The flow of air was so adjusted that the temperature of thecatalyst did not exceed 490 C. at any point. When the temperature of thecatalyst bed had fallen to 450 C. again the nitrogen fiow was stoppedand air was passed over the granules. The catalyst was then heated at650 C. for 16 hours.

The catalyst was placed in a reactor maintained at 400 C., and a gasmixture comprising 10.8% by volume of propylene, 51% by volume of air,and 38.2% by volume of steam was passed over the catalyst, the contacttime being 4 seconds.

30.5% of the propylene ted was converted into acrolein and 4.5% tocarbon dioxide. The yield of acrolein based on propylene consumed was74%.

Example 9 259.6 parts by weight of antimony pentachloride were addeddropwise to a vigorously stirred solution of 913 parts by weight ofstannic chloride in 3000 parts by weight of water. When the addition wascomplete the pH of the suspension was adjusted to 5.5 by the addition ofconcentrated ammonia solution. The temperature of the mixture was raisedto 90 C. for 5 minutes, cooled to 25 C. and the precipitate filteredoff, washed with water and dried. The catalyst was then heated at 400 C.to 430 C. in air for 5 hours, pelleted, heated at 725 C. for 16 hours,and finally at 900 C. for 16 hours.

The catalyst was placed in a reactor maintained at 440 C., and a gaseousmixture of propylene (10.5% by volume), air (50.7% by volume), and steam(38.8% by volume) was passed over the catalyst, the contact time being 4seconds.

Of the propylene fed, 34.8% was converted to acrolein and 6.3% to carbondioxide. The yield of acrolein based on propylene consumed was 68%.

Example 190 parts by weight of powdered tin metal were slowly added to awell stirred solution of 800 parts by volume of nitric acid (S.G. 1.42)dissolved in 3200 parts by weight of water. During the addition the acidwas maintained at its boiling point. 97.6 parts by weight of powderedantimony metal were added to 400 parts by volume of nitric acid (S.G.1.42) with stirring. Both acid mixtures were boiled with stirring untilno more brown nitrous fumes were evolved. The antimony oxide suspensionwas then added to the tin mixture and stirred for several minutes. Themixture was filtered, washed with distilled water, dried, and theresulting powder mixed with 2% by weight of graphite and pelleted. Thecatalyst was then heat-treated at 700 C. for 16 hours, and finally at1000 C. for 16 hours.

The catalyst was placed in a reactor maintained at 440 C. and a gaseousmixture of 10% by volume of propylene, 70% by volume of air and 20% byvolume of steam was passed over the catalyst, the contact time being 4seconds.

Of the propylene fed, 40.2% was converted to acrolein and 7.5% to carbondioxide. The yield of acrolein based on propylene consumed was 70.4%.The activity of this catalyst did not decrease after a run of 74 hours.

Example 11 A catalyst comprising antimony oxide and tin oxide wasprepared as described in Example 10, and was deposited on silica gel.

The catalyst was placed in a reactor maintained at 477 C., and a gaseousmixture consisting of 9.9% by volume of propylene, 51.3% by volume ofair and 38.8% by volume of steam was passed over the catalyst, thecontact time being 3.9 seconds.

Of the propylene fed, 37.2% was converted to acrolein and 9.4% to carbondioxide. The yield of acrolein based on propylene consumed was 63.1%.

Example 12 Powdered tin (47.5 parts by weight) was added in smallportions to a boiling solution of nitric acid (284 parts by weight ofconcentrated nitric acid in 800 parts by weight of water). Powderedantimony (24.4 parts by weight) was added in small portions to warmconcentrated nitric acid (142 parts by weight). Both mixtures wereboiled until no further brown nitrous fumes were evolved. While stillhot the antimony oxide suspension was added to the tin mixture withstirring, and after 5 minutes the precipitate was filtered ofi, washedwith water and resuspended in 100 parts by weight of water. The mixturewas then added to silica gel (22.8 parts by weight of SiO in 811 partsby weight of water) and the solids were thoroughly mixed by stirring.The solids were then filtered 01f, dried, and sieved to give granules ofless than mesh B.S.S., and finally heated in air at 800 C. for 16 hours.

34 parts by weight of the catalyst were placed in a inch diameterreactor maintained at 459 C. The catalyst was fluidized by admitting agaseous feed of 9.5% by volume of propylene, 49.7% by volume of air and40.8% by volume of steam at a flow rate of 25,330 parts by volume/hour,measured at N.T.P.

Of the propylene fed 29.7% was converted to acrolein Example 13 Acatalyst was prepared by intimately mixing 32 parts by'weight oftellurium dioxide and 65 parts by weight of antimony pentoxide, firstlyas a fine powder and then with the addition of a small amount of waterto form a paste. The mixture was dried, pelleted and heat-treated at 450C. for 16 hours.

The catalyst was placed in a reactor maintained at 402 C., and a gaseousmixture comprising 11.6% by volume of propylene, 49.1% by volume of airand 39.3% by volume of steam was passed over the catalyst, the contacttime being 8.6 seconds.

Of the propylene fed, 16.2% Was converted to acrolein and 4.4% to carbondioxide. The yield of acrolein based on propylene consumed was 52.4%.

Example 14 A catalyst was prepared by intimately mixing 16 parts byweight of titanium dioxide and 64.6 parts by weight of antimonypentoxide. After pelleting, the catalyst was heat-treated at 540 C. for16 hours.

The catalyst was placed in a reactor maintained at 423 C. and a gaseousmixture of 11.2% by volume of propylene, 48.1% by volume of air, and40.7% by volume of steam was passed over the reactor, the contact timebeing 3.1 seconds.

Of the propylene fed to the reactor, 6.7% was converted to acrolein and2.7% to carbon dioxide. The yield of acrolein based on propyleneconsumed was 49.6%.

Example 15 A catalyst was prepared by mixing a hot solution of 29.1parts by weight of cobalt nitrate (Co (NO .6H O) in 100 parts by weightof water with a boiling solution of 50.8 parts by weight of potassiumantimonate (K H Sb O .4H O) in 750 parts by weight of Water.

The precipitate was filtered ofi, washed with boiling water, dried andsieved to give 8 to 16 mesh B.S.S. granules.

The catalyst was placed in a reactor maintained at 400 C., and a gaseousmixture of 10.3% by volume of propylene, 52.6% by volume of air, and37.1% by volume of steam was passed over the catalyst, the contact timebeing 4 seconds.

Of the propylene fed, 5.8% was converted to acrolein and 5.2% to carbondioxide. The yield of acrolein based on propylene consumed was 32%.

Example 16 A catalyst was prepared by dissolving 127 parts by weight ofpotassium antimonate in 2,000 parts by weight of boiling water. Thesolution was cooled to room temperature and mixed with a solution of60.4 parts by weight of copper nitrate in 500 parts by weight of water.The precipitate was filtered off, washed and dried.

The catalyst was placed in a reactor maintained at 393 C., and a gaseousmixture of 11.1% by volume of propylene, 48.7% by volume of air and40.2% by volume of steam was passed over the catalyst, the contact timebeing 3.0 seconds.

Of the propylene fed to the reactor, 8.3% was con verted to acrolein and9.2% to carbon dioxide. The yield of acrolein based on propyleneconsumed was 39%.

Example 17 A solution of 45.1 parts by weight of stannous chloride (SnCl.2H O) in 100 parts by Weight 1% hydrochloric acid solution, was mixedwith a solution of 119.9 parts by weight of antimony pentoxide in 2,000parts by weight of water. The mixture was heated to C. and concen tratedammonia was then added to bring the pH to 6.5. After boiling themixture, the precipitate was filtered off,

acrolein and 6.8% to carbon dioxide. methacrolein based on isobuteneconsumed was 40% methacrolein based on isobutene consumed was 23%Example 18 104.8 parts by weight of antimony pentachloride, were addedto 1500 parts by weight of water with stirring, and at the same time asolution of 61.45 parts by weight of stannic chloride (SnCl .5H O) in100 parts by weight of 1% hydrochloric acid solution was added dropwise.When the addition was complete, the mixture was heated to 96 C. for 5minutes, cooled to 22 C. and diluted with 500 parts by weight of water.The pH was then adjusted to 5.1 with dilute ammonia solution. Theprecipitate ;was filtered off, washed in water, dried, heated in astream of air at 380 C. for 2 hours and finally at 540 C. for 16 hours.The catalyst was then sieved to give 8-16 mesh .B.S.S. granules.

The catalyst was placed in a reactor maintained at 334 C., and a gaseousmixture of 10% by volume of isobutene, 50% by volume of air, and 40% byvolume of .steam was passed over the catalyst, the contact time being 4seconds.

Of the isobutene fed, 12.8% was converted to meth- The yield of Example19 A catalyst was prepared by intimately mixing 16 parts by weight oftitanium dioxide (TiO and 64.8 parts by weight of antimony pentoxide.After being pelleted, the catalyst was heated in air at 540 C. for 16hours before use.

The catalyst was placed in a reactor maintained at 405 C. and a gaseousmixture of 10% by volume of isobutene, 50% by volume of air, and 40% byvolume of steam was passed over the catalyst, the contact time being 3seconds.

Of the isobutene fed, 5.5% was converted to methacrolein and 1.2% tocarbon dioxide. The yield of methacrolein based on isobutene consumedwas 36%.

Example 20 A catalyst was prepared by mixing a solution of 105.2 partsby weight of potassium m-antimonate (KSbO 3H O) in 1500 parts by volumeof hot water with a solution of 48.3 parts by weight of cupric nitrate(Cu(NO .3H O) in 200 parts by volume of water. After maintaining themixture at 70 C. for minutes, the precipitate of copper antimonate wasfiltered oil and Washed twice with hot water. The precipitate wasfinally dried in air and sieved to 8 to 16 mesh B.S.S. before use.

The catalyst was placed in a reactor maintained at 345 C. and a gaseousmixture of 10% by volume of isobutene, 50% by volume of air and byvolume of steam, was passed over the catalyst, the contact time being 4seconds.

'verted to acrolein and 6% to carbon dioxide.

Of the isobutene fed, 12.4% was converted to methacrolein and 3.1% tocarbon dioxide. The yield of methacrolein based on isobutene consumedwas 55%.

Example 21 The process of example 20 was repeated using a cobaltantimonate catalyst prepared by precipitation from mixed solutions ofcabaltous nitrate and potassium m-antimonate. The reaction temperaturewas 394 C.

Of the isobutene fed, 12.1% was converted to methacrolein and 4.1% tocarbon dioxide. The yield of methacrolein based on isobutene consumedwas 51%.

Example 22 144 parts by weight of molybdenum trioxide (M00 wereintimately mixed with 323.5 parts by weight of antimony pentoxide, firstas dry powders and then as a wet paste with a little water. The mixturewas dried, sieved to 30 to mesh B.S.S. pelleted and heated in air at 540C. for 16 hours.

The catalyst was placed in a reactor maintained at 424 C. and a gaseousmixture of 10% by volume of isobutene, 50% by volume of air and 40% byvolume of steam was passed over the catalyst, the contact time being 2seconds.

Of the isobutene fed, 21% was converted to methacrolein, and 4.9% tocarbon dioxide. The yield of methacrolein based on isobutene consumedwas 56%.

Example 23 The process of Example 22 was repeated using a propylenefeed.

Of the propylene fed to the reactor, 12.2% was con- The yield ofacrolein based on propylene consumed was 41.3%.

By way of comparison with the above examples, a process was carried outin which a feed of 10% by volume of propylene, 50% by volume of air, and40% by volume of steam was passed over a stannic, oxide catalystmaintained in a reactor at 360 C., the contact time being 4 seconds.

Cf the propylene fed, 1.9% was converted to acrolein and 6.5% to carbondioxide.

The yield of acrolein based on propylene consumed was 16%.

We claim:

A catalyst consisting essentially of a mixture of stannic oxide withantimony tetroxide, the atomic ratio of tin to antimony in said catalystbeing from about 0.1:1 to about 10:1.

References Cited by the Examiner UNITED STATES PATENTS 1,661,826 3/28Hessle 252461 X 2,250,415 7/41 Burk ct al 265-464 X 2,360,689 lO/44Kipper 252-461 X 2,410,044 10/46 Burk et a1 252464 X 2,63 8,455 5/53Pitzer 252464 X 2,668,142 2/54 Strecker et al 252464 X 2,783,185 2/57Hughes et al 252--464 X 3,013,089 12/61 Estes et a1 252-464 X 3,094,5526/63 Wood 252-461 X FOREIGN PATENTS 718,723 11/54 Great Britain.

MAURICE A. BRINDISI, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3 ,l98,751 August 3, 1965 James Robert Bethell et a1 It is hereby certifiedthat error appears in the above numbered patent requiring correction andthat the said Letters Patent should read as corrected below.

Column 2, line 22, for "01.1.:1" read 0.1:1 column 3, line 22, for "of600 C." read at 000" C. line 74, for "111.9" read 11909 column 6, line10, for "450 C," read 540 C. column 8, line 8, for "cabaltous" readcobaltous Signed and sealed this 18th day of January 1966 (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

